scholarly journals Load Transfer Along the Bone-Implant Interface and Its Effects on Bone Maintenance

10.5772/18433 ◽  
2011 ◽  
Author(s):  
Samira Faegh ◽  
Hsuan-Yu Chou ◽  
Sinan Muftu
Keyword(s):  
Load Transfer ◽  
Bone Implant ◽  
Bone Maintenance

scholarly journals Finite Element Analysis of Tibial Bone-Implant Load Transfer and Bone Strains with a Modern Fixed-bearing Total Ankle Replacement

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0011
Author(s):  
Daniel Sturnick ◽  
Guilherme Saito ◽  
Jonathan Deland ◽  
Constantine Demetracopoulos ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Tibial Component ◽  
Load Transfer ◽  
Young's Modulus ◽  
Stress Shielding ◽  
Poisson's Ratio ◽  
Bone Implant ◽  
Tibial Tray ◽  
Tibial Bone

Category: Ankle Arthritis Introduction/Purpose: Loosening of the tibial component is the primary failure mode in total ankle arthroplasty (TAA). The mechanics of the tibial component loosening has not been fully elucidated. Clinically observed radiolucency and cyst formation in the periprosthetic bone may be associated with unfavorable load sharing at and adjacent to the tibial bone-implant interface contributory to implant loosening. However, no study has fully investigated the load transfer from the tibial component to the bone under multiaxial loads in the ankle. The objective of this study was to utilize subject-specific finite element (FE) models to investigate the load transfer through tibial bone-implant interface, as well as periprosthetic bone strains under simulated multiaxial loads. Methods: Bone-implant FE models were developed from CT datasets of three cadaveric specimens that underwent TAA using a modern fixed-bearing tibial implant (a cobalt-chrome tray with a polyethylene bearing, Salto Talaris, Integra LifeSciences). Implant placement was estimated from the post-operative CT scans. Bone was modeled as isotropic elastic material with inhomogeneous Young’s modulus (determined from CT Hounsfield units) and a uniform Poisson’s ratio of 0.3. The tibial tray (Young’s modulus: 200,000 MPa, Poisson’s ratio: 0.3) and the polyethylene bearing (Young’s modulus: 600 MPa, Poisson’s ratio: 0.4) were modeled as isotropic elastic. A 100-N compressive force, a 300-N anterior force, and a 3-Nm moment were applied to two literature based loading regions on the surface of the polyethylene bearing. The proximal tibia was fixed in all directions. The bone-implant contact was modeled as frictional with a coefficient of 0.7, whereas the polyethylene bearing was bonded to the tray. Results: Along the long axis of the tibia, load was transferred to the bone primarily through the flat bone-contacting base of the tibial tray and the cylindrical top of the keel, little amount of load was transferred to the bone between those two features (Fig. 1A). Low strain was observed in bone regions medial and lateral to the keel of the tibial tray, where bone cysts were often observed clinically (Fig. 1A). On average, approximated 70% of load was transferred through the anterior aspect of the tibial tray at the flat bone-contacting base, which corresponded to the relatively high bone strain adjacent to the implant edge in the anterior bone-implant interface (Fig. 1B). Conclusion: Our results demonstrated a two-step load transfer pattern along the long axis of the tibia, revealing regions with low bone strain peripheral to the keel indicative to stress shielding. Those regions were consistent with the locations of bone cysts observed clinically, which may be explained by the stress shielding associated remodeling of bone. These findings could also describe the mechanism of implant loosening and failure. Future studies may use our model to simulate more loading scenarios, as well as different implant placement and design, to identify means to optimize load transfer to the bone and prevent stress shielding.

The role of fluid hydrostatic pressure in bone-implant interface load transfer

1984 ◽  
Vol 12 (6) ◽  
pp. 559-571
Author(s):  
Jack L. Lewis ◽  
Cary Keller ◽  
S. David Stulberg ◽  
John Steege ◽  
Michael Santare
Keyword(s):  
Hydrostatic Pressure ◽  
Load Transfer ◽  
Bone Implant

Load Transfer Along the Bone-Dental Implant Interface

2009 ◽  
Author(s):  
Samira Faegh ◽  
Sinan Müftü
Keyword(s):  
Dental Implants ◽  
Load Transfer ◽  
Surface Characteristics ◽  
Systematic Investigation ◽  
Long Term Results ◽  
Implant Design ◽  
Patient Specific ◽  
Success Rates ◽  
Bone Implant ◽  
Patient Specific Implants

Endosseous dental implants are used as prosthetic treatment alternatives for treating partial edentulism [1]. Excellent long term results and high success rates have been achieved using dental implants during the past decades. Further improvements in implant protocols will include immediate loading, patient specific implants, applications for patients with extreme bone loss and extreme biting habits such as bruxism. The implant designs available in the market vary in size, shape, materials and surface characteristics [2], and address some of these concerns. An important factor in the implant design is the load transfer from the implant to bone during occlusal loading.[2,3] Load transfer starts along the bone-implant interface, and is affected by the loading type, material properties of the implant and prosthesis, implant geometry, surface structure, quality and quantity of the surrounding bone, and nature of the bone-implant interface [4]. While many studies using the finite element method (FEM) have been carried out [2–5], a systematic investigation of the load transfer at the bone implant interface, and the effects of various parameters that make the implant contour is lacking. The goal of this paper is to investigate one aspect of this multivariable problem, namely the effect of external implant threads on the load transfer along the bone-implant interface.

scholarly journals Bone ongrowth and mechanical fixation of implants in cortical and cancellous bone

2020 ◽  
Author(s):  
William Robert Walsh ◽  
Matthew Henry Pelletier ◽  
Nicky Bertollo ◽  
Vedran Lovric ◽  
Tian Wang ◽  
...  
Keyword(s):  
Load Transfer ◽  
Large Animal Model ◽  
Large Animal ◽  
Biological Fixation ◽  
Implant Surface ◽  
Bone Implant ◽  
Titanium Coatings ◽  
The Right ◽  
Plasma Sprayed

Abstract Background What is the right surface for an implant to achieve biological fixation? Surface technologies can play important roles in encouraging interactions between the implant surface and the host bone to achieve osseointegration. Pre-clinical animal models provide important insight into in-vivo performance related to bone ongrowth and implant fixation.Methods A large animal model was used to compare the in vivo response of HA and plasma sprayed titanium coatings in a well reported adult ovine model to evaluate bone ongrowth in terms of mechanical properties in cortical sites, histology and histomorphometry in cortical and cancellous sites at 4 and 12 weeks. Results Titanium plasma sprayed surfaces outperformed the HA coated samples in push-out testing in cortical sites while both surfaces supported new bone ongrowth and remodeling in cortical and cancellous sites. Conclusions While both HA and Ti plasma provided an osteoconductive surface for bone ongrowth, the Ti plasma provided a more robust bone-implant interface that ideally would be required for load transfer and implant stability in the longer term.

Numerical Evaluation of Biomechanical Stresses in Dental Bridges Supported by Dental Implants

2018 ◽  
Vol 37 ◽  
pp. 43-54 ◽  
Author(s):  
Amel Boukhlif ◽  
Ali Merdji ◽  
Noureddine Della ◽  
El Bahri Ould Chikh ◽  
Osama Mukdadi ◽  
...  
Keyword(s):  
Dental Implants ◽  
Load Transfer ◽  
Three Dimensional ◽  
Surgical Techniques ◽  
Von Mises Stress ◽  
Bone Implant ◽  
External Part ◽  
Von Mises ◽  
Von Mises Stresses ◽  
The Impact

The number of supporting dental implants is an important criterion for the surgical outcome of dental bridge fixation, which has considerable impact on biomechanical load transfer characteristics. Excessive stress at the bone–implant interface by masticatory loading may result in implant failure. The aim of this study was to evaluate the impact of the number of implants supporting the dental bridge on stress in neighboring tissues around the implants. Results of the study will provide useful information on appropriate surgical techniques for dental bridge fixation. In this study, osseointegrated smooth cylindrical dental implants of same diameter and length were numerically analyzed, using three-dimensional bone–implant models. The effect of the number of supporting implants on biomechanical stability of dental bridge was examined, using two, three and four supporting implants. All materials were assumed to be linearly elastic and isotropic. Masticatory load was applied in coron-apical direction on the external part of dental bridge. Finite Element (FE) analyses were run to solve for von Mises stress. Maximum von Mises stresses were located in the cervical line of cortical bone around dental implants. Peak von Mises stress values decreased with an increase in the number of implants that support the dental bridge. Results of this study demonstrate the importance of using the correct number of supporting implants to for dental bridge fixation.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

Factors influencing adhesive bonding at the bone/implant interface

1992 ◽  
Vol 50 (2) ◽  
pp. 1114-1115
Author(s):  
Julie A. Martini ◽  
Robert H. Doremus
Keyword(s):  
Electron Microscopy ◽  
Adhesive Bonding ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Bone Implant ◽  
Factors Influencing ◽  
Lr White ◽  
Transmission Electron ◽  
New Zealand White Rabbits ◽  
Scanning Electron

Tracy and Doremus have demonstrated chemical bonding between bone and hydroxylapatite with transmission electron microscopy. Now researchers ponder how to improve upon this bond in turn improving the life expectancy and biocompatibility of implantable orthopedic devices.This report focuses on a study of the- chemical influences on the interfacial integrity and strength. Pure hydroxylapatite (HAP), magnesium doped HAP, strontium doped HAP, bioglass and medical grade titanium cylinders were implanted into the tibial cortices of New Zealand white rabbits. After 12 weeks, the implants were retrieved for a scanning electron microscopy study coupled with energy dispersive spectroscopy.Following sacrifice and careful retrieval, the samples were dehydrated through a graduated series starting with 50% ethanol and continuing through 60, 70, 80, 90, 95, and 100% ethanol over a period of two days. The samples were embedded in LR White. Again a graduated series was used with solutions of 50, 75 and 100% LR White diluted in ethanol.

Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

1992 ◽  
Vol 50 (1) ◽  
pp. 158-159
Author(s):  
Warren J. Moberly ◽  
Daniel B. Miracle ◽  
S. Krishnamurthy
Keyword(s):  
Thermal Stresses ◽  
Load Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Hot Isostatic Pressing ◽  
Matrix Composites ◽  
Ongoing Research ◽  
Aerospace Applications ◽  
Sic Fiber ◽  
The Matrix ◽  
Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

Definition of load transfer curves of piles in granitic residual soil

Geotecnia ◽  
2014 ◽  
Vol 130 ◽  
pp. 79-99
Author(s):  
David Jorge Pereira Fernandes ◽  
◽  
<br>António Viana da Fonseca ◽  
Keyword(s):  
Load Transfer ◽  
Residual Soil ◽  
Definition Of
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